Controlled beam high intensity flood lamp



April 6, 1965 Filed July 7, 1961 A. l. APPLETON CONTROLLED BEAM HIGH INTENSITY FLOOD LAMP 2 Sheets-Sheet 1 INVENTOR.

April 6. 1965 A. I. APPLETON 3,177,354

CONTROLLED BEAM HIGH INTENSITY FLOOD LAMP Filed July 7. 1961 I 2 Sheets-Sheet 2 INV EN TOR.

United States Patent 3,177,354 CONTROLLED BEAM HIGH INTENSITY FLOOD LAMP Arthur I Appleton, Northbrook, Ill. Appleton Electric (30., 1713 Wellington Ave., Chicago, Ill.) Filed July 7, 1961, Ser. No. 122,553 2 Claims. (Cl. 240-3) response to this demand, there-has been a trend toward the use of light fixtures utilizing lamps capable of producing extremely high intensity illumination. Iodine cycle type flood lamps have recently been developed which,

despite their small size and low cost, are capable of producing the desired degree of illumination. 7

However, as light fixtures capable of producing higher and higher degrees of illumination intensity have been developed and put into commercial use, the problem of heat produced by the lamp has become acute. The external heat developed by such fixtures has a direct and detrimental effect on working conditions which results in lowcaliber performance by both actors and stage hands. Moreover, and completely aside from the discomfort to which individuals are subjected, the heat developed has resulted in ashorter life expectancy for props and other equipment, for example, electrical wiring facilities.

With the advent of color television, still another prob-' lem has been encountered and emphasized. Photographic equipment is extremely sensitive to difierent portions of theoptical spectrum. It has been found that certain colors produce adverse effects and are, therefore, highly undesirable, not only-in color television work, but also in color motion picture Work and photographic studio work. i I

7 It is thege'neral aim of-the present invention to provide a new and improved flood lamp assembly in which all of the advantages of a high intensity light source are retained yet wherein the aforementioned disadvantages resulting from heat developed by the lamp are eliminated.

' It is another object of the invention to provide a flood lamp assembly for illuminating objects in which the light in the beam directed towards the object is confined to the relatively cool portion of the optical spectrum. I I More specifically, it is an object of the invention to provide a flood lamp assembly in which the visible portion of the optical spectrum of light emanating therefrom is directed'toward the object to be illuminated while the infrared portion of the optical spectrum is directed away from the object. e

' In another one of its aspects, it is an object of the invention to provide a flood lamp assembly in which only a predetermined portion. of the visible light spectrum is directed toward the object to be illuminated. In this manner the present invention contemplates a flood lamp assembly wherein undesirable wavelengths of color are directed away from the object to be illuminated thus producing better control for color photographic equipment.

Still another object of the invention is to provide a flood lamp assembly in which both the objectionable wavelengths of color in the optical spectrum and the infrared spectrum are directed away from the object to be illuminated.

A further object of the invention is to provide a flood lamp assembly characterized by its ability to project substantially all of the visible light emanating therefrom towards the object to be illuminated, while the major portion of the heat produced by the light source is directed away from the object.

Other objects and advantages will appear from the following description taken in conjunction with the accompanying drawing, in which:

FIGURE 1 is a side elevation, partly in section, of an exemplary flood lamp assembly embodying the features of the present invention;

FIG. 2 is a view taken substantially along the line 2-2 of FIG. 1 with a portion of the mirror cut away to illustrate the interior of the housing;

FIG. 3 is a simplified line diagram illustrating a typical use of flood lamps embodying the features of the present invention; and

FIG. 4 is a diagrammatic perspective view illustrating the use of a plurality of the flood lamps of the present invention in a battery together with a novel cooling arrangement, partly broken away, to further dissipate the heat produced by'the lamps.

While the present invention is susceptible of various modifications and alternative constructions, an illustrative embodiment is shown in the drawing and will herein be decribed in detail. It should be understood, however, that it is not intended to limit the invention to the particular form disclosed, but, on the contrary, the'intention is to cover all modifications, equivalents and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

Referring now to FIGS. 1 and 2, an exemplary flood lamp assembly, generally indicated at 10, is illustrated. As the description proceeds, it will be appreciated that the novel features of the present invention will find use with a wide variety of flood lamp fixtures. However, the invention is here illustrated and described in connection with a flood lamp fixture of the type utilizing an iodine cycle type lamp. Such a flood lamp fixture is described in detail in the copending application of Arthur 1. Appleton, Serial No. 66,008, filed August 31, 1960, now abandoned.

It should suflice for the purpose of the present description to say that the flood lamp assembly 10 includes a generally trough-shaped lamp housing 11 which houses an iodine cycle type lamp 12 having an electrode at each end thereof. The lamp housing 11 is swivelly mounted on a terminal; assembly 14, thus enabling the light beam emanating from the housing to be directed in any desired vertical plane. The terminal assembly 14 is telescopically mountedon a pipe-like support so as to be rotatable with respect thereto. Threaded fasteners 16 are provided for securely locking the lamp assembly 10 to the support 15 in any desired position, thereby enabling the flood lamp to be aimed in a desired horizontal direction. An access opening, generally indicated at 18, is provided in the terminal assembly 14 and provides means for receiving the electrical wiring facilities (not shown). Suitable cooling fins 19 are integrally formed on the exterior surfaces of the lamp housing ll.

Provision is made for directing a sharp and precisely controlled beam of high intensity illumination from the 7 microns.

lamp assembly 10. To accomplish this, a parabolic trough reflector 20 (FIG. 2) is securely mounted within the housing 11, for example, by threaded fasteners, one of which is shown at 21. A pair of end reflectors, one of which 1s shown at 22, are mounted inthe lamp housing 11 with each end reflector having a peripheral contour conforming to the inside shape of the parabolic reflector 20. The endrrefiectors 22 are each provided with an opening 24 positioned to receive the opposite ends of the elongated iodine cycle type lamp 112. The lamp is received in sockets '(notshown) in such a manner that the lamp filament is suspended along the focal axis of the parabolic reflector 20. The foregoing arrangement insures that a high intensity beam of light is directed out of the lamp housing along the axis indicatedby the arrow L.

In order to have a complete understanding of the present invention, it will be appreciated that the beam of light emanating from the flood lamp assembly along the axis L is composed of radiant energy in the optical spectrum. The optical spectrum, in turn, is simply a portion of the physical spectrum of radiant energy. It can be generally stated that radiant energyis classified in the physical spectrum in accordance with its wavelengths. Thus, the physical spectrum includes,in increasingrorder of wavelengths, the following spectra:

Gamma rayspectrum Xray spectrum Ultraviolet spectrum Visible or ocular spectrum Infrared spectrum Electro magnetic-wave spectrum The optical spectrum, with which the present invention is concerned, consists of the ultraviolet, visible and infrared spectra. It should suffice for-this description to state that the ultraviolet spectrum includes radiant. energy having wavelengths less than 380 millimicrons (380 me) while the infrared spectrum includes radiant energy, having wavelengths greater than 760 millimicrons (760 m The visible or ocularspectrum includes all radiant energy having wavelengths in the range of 380-760 mili- Radiant energy in the visible spectrum may be further subdivided into the following ranges of wavelengths which correspond to theparticular indicated colors:

380-450 m,uviolet 450-490 m t-blue 560-590 mil-yellow 590-630 m,uorange It is generally known that, While all wavelengths of radiant energy in both the visible and infrared spectra produce heat or thermal actions when properly absorbed,

the principal source of heatis infrared radiant energy. The present invention is primarily concernedwith providing a novel flood lamp assembly in which the relatively. hot infrared rays are directedaway from the ob ject to be illuminated, while the relatively cooler wavelengths of radiant energy in the visible spectrum are directed towards the object.

comprising a different portion of the optical spectrum,

V such plate 30 being shown in FIG. 1).

spectrum and transmit light in the infrared spectrum, a dichroic mirror is utilized in which radiant energy having wavelengths greater than 760 millimicrons are transmitted and'radia'nt energy havingwavelengths less than 760- millimicrons are reflected. This is accomplished by providing a coating on one or both surfaces of the mirror, which coating exhibits dichroic, properties. In the. illustrative form of the invention, a coating 25a is'applied to the rear surface of the mirror 25 (FIG. 1). The type of coating used is not critical tothe present invention so long as it is capable of reflecting the desirable wavelengths and transmitting the undesirable wavelengths. Thus, the coating 25a may be'a multi-layer coating with alternate layers of high andv low index materials, i.e., zincsulfide and cryolite, such, for example, as described in US. Patent No. 2,552,184 m G. J. Koch.

Of course, it is not intended to limit the present invention to flood lamp assemblies utilizing only the reflected rays since in certain instances, it might be desirable to reflect the undesirable wavelengths-and to transmit the desirable wavelengths. e

In carryingout the present invention,.the dichroic mirror 25 is preferably rigidly secured to. the lamp housing 11. To accomplish this, the mirror 25 is mounted in a rectangular frame 26 having a channel shaped crosssection. Brackets 28, integral With one lateral edge of the frame 26, are rigidly secured to the lamphousing 11,

for example, by threaded fasteners 29. The mirror 25 is held in a fixed angular position relative to the axis L of the beam of light emanating from the housing 11 by means of a pair of laterally spaced support plates 30 (one Each plate 30 is rigidlysecured along one edge thereof to the housing 11 and at the oposite edge thereof .to one side of the mirror frame 26. 7 1

In order to obtain themaximum amount of reflected illumination, the mirror 25 is mounted on the housing 11 at an included angle of with respect to the face of the housing -(FIG.-1). The mirror 25 isfurther designed for use with a lightbeam impinging upon the mirrorwith'an-angle of incidence of 45, the angle of incidence being the included angle ibetween. the axis L of the lightbeam emanating from the housing and a line normal to the mirror at the point'where the axisL .of the beam strikes; the reflective surface of the mirror.

tion, the radiant energy reflected by 'themirror will be reflected at an angle of 90 with respect to the axis L of the beam emanating from the housing 11. It'will be apparent by reference to FIG. 1 that the angle .of reflection is the included angle 'r betweenthe axis L, of the reflected light beam and the line normal to the mirror at the point of intersection of the mirror and the. axis L. Since the axis L of the, reflected light-beamis perpendicular to. the axis L, none of the radiant energyreflected from the mirror 25 is projectedback into the housing. To the contrary, all of the light reflected from the mirror is directed toward theobjectto be illuminated. 3

In the preferred embodiment, this is accomplished by positioning a dichroic mirror 25 in the path of the beam e ing a diiferentrange of wavelengths (beam L When, for example, it is desired toireflect light in, the visible To'further increase the intensity of the light reflected along the axis L,, the internal surface. of the support plates'30 may be polished so as to provide highly reflective surfaces. Moreover, *the support plates 30 may; be provided with external cooling fins 31' if desired or, alter-.

-nat ively,'with.louvers (notIshownyto increase the circulanon of cooling air. vThus, the plates 30 simultaneously perform the functionsofholding the mirror in, a fixed angular position, increasing the intensity of illumination, and aiding in cooling the flood lamp, assembly 10. i a

While the present invention will operate with a flood V lampessernbly having a lens, panel assembly of the type described in the aforementioned copending application of Arthur I. Appleton, it is. preferable toutilize a flood lamp in which the lens panel assembly 'is removed.

In practice it has been found that the results achieved 7 with floodlamps employing the features of the present Since. the angle of incidence i is equal to. the angleof-the reflecinvention are extremely beneficial, both to performance of personnel and to equipment. Merely by way of example, it has been found that when using an iodine cycle type flood lamp with acontrolled operating voltage of 277v., amperage of 5.4 amps'and wattage of 1500 watts, the temperature at a distance of two feet from the mirror along the axis L is 105 F. Six feet from the mirror the temperature is 79 F. Without the use of the dichroic mirror the temperature at a distance of 2 feet from the lamp 12 along the axis L is 274 F. and at a distance of six feet the temperature is 102 F.

The present invention is particularly suitable for use in color television, color motion pictures and photographic studios. In these applications it is often desirable to control the color of the reflected illumination as well as the temperature of the reflected beam. Thus, if in a particular lighting application, it is found that a certain color, or range of colors, is producing undesirable effects,

it is possible to alleviate the problem with the use of a dichroic mirror having a slightly different coating applied thereto. For example, in those lighting applications where the red portion of the visible spectrum is producing undesirable effects, all of the red spectrum can be eliminated simply by selecting a dichroic coating for the mirror with characteristics capable of transmitting radiant energy having a wavelength greater than 630 millimicrons and reflecting nadiant energy having a wavelength less than 630 millimicrons. In this instance, the blue portion of the visible spectra would be emphasized in the reflected light. Moreover, any desired portion of the red spectrum can be transmitted while the remainder is reflected simply by appropriate selection of the coating on the mirror.

Referring now to FIG. 3, there is illustrated in simplified line form, a typical photographic lighting arrangement employing :a pair of flood lamp assemblies each embodying the features of the present invention. In this simplified arrangement, the flood lamps are carried by portable tripods 15 each having an upwardly extending pipe-like support 15 which is telescopically received within the terminal assembly 14 (FIGS. 1 and 2). The flood lamps and their associated dichroic mirrors 25 are positioned so that the desirable portion L of the optical spectrum is reflected downwardly toward the person or object to be illuminated (generally indicated at 32). At the same time, the undesirable portion L of the optical spectrum, for example, heat producing infrared radiant energy, is transmitted through the dichroic mirrors 25 and directed upwardly away from the person or object 32.

In keeping with the present invention, provision is made for utilizing high intensity flood lamp assemblies in batteries and for simultaneously dissipating both the heat produced by the transmitted light beams L and the heat absorbed by the flood lamp assemblies 10. To this end, a plurality of flood lamp assemblies 10 are mounted adjacent to one another in a battery 34, there being three such flood lamp assemblies ltla-ltlc in the exemplary battery 34 shown diagrammatically in FIG. 4. An elongate metallic duct, here shown as substantially an inverted trough 35, is positioned over the adjacent mirrors 25a-25c and in spaced relation thereto with the mirrors received within the open side of the trough.

-The opposite ends of the trough are closed by end walls 36, 38. The duct 35 may be rigidly secured in a fixed position relative to the mirrors 25a-25c in a variety of ways, for example, by mounting the duct on the structural supporting framework 39 (shown diagrammatically) of the battery 34, or by physically attaching the duct to' are preferablymounted on their asso'ciated lamp housings 11a-11c between a pair of laterally spaced support plates 30a, 30b similar to the plates 30 shown in FIG. 1, but dimensioned such that the mirrors 25a-2Sc are spaced from the lamp housings Ila-11c respectively by a fixed distance x at their closest point. In this manner, the actionof the fan 40 creates a stream of cooling air indicated by the arrow s which flows over the lamp housings lla-llc and through the open spaces between the mirrors and the housings and the open spaces between the mirrors and the duct. Further cooling may be obtained by laterally spacing adjacent lamp housings and mirrors a fixed distance y such that cooling air is carried between adjacent housings and adjacent support plates. In this latter instance, the battery of lamp assemblies may be disposed about a wide area surrounding, for example, a stage, in which case the distance y may be several feet. The duct would, in such instances, be given a straight line or curved longitudinal configuration to the spacing and arrangement of the individual lamp assemblies in the battery. In this type of cooling arrangement it will be desirable to close the bottom portion of the duct throughout a substantial portion of the intervening distances y leaving spaced openings therein corresponding to the locations of the lamps.

It will be apparent that there has been disclosed an improved and novel flood lamp assembly characterized by its ability for directing a beam of cool light towards a stage or other object to be illuminated while transmitting the heat producing portions of the infrared spectrum away from the stage. Moreover, by appropriate selection of the dichroic material on the mirror, it is possible to control the hues projected from the flood lamp assembly with a great deal of accuracy, thereby preventing undesirable colors from being projected. Additionally, since the trough shaped reflector 20 is considerably closer to the light source 12 than is the mirror 25, a portion of the heat produced by the light will be absorbed by the metallic reflector 20 and the housing 11, thus tending to minimize the heat present at the mirror and enhancing the life of the mirror.

Of course, While the illustrative embodiment of the present invention has been shown in conjunction with a dichroic mirror 25 of planar form, those skilled in the art will readily appreciate that the particular shape of the mirror and the particular dichroic coating or coatings applied thereto will depend upon the desired shape of the reflected light beam L, emanating therefrom.

I claim as my invention:

1. For use in illuminating theatrical stages or the like the combination comprising, a plurality of flood lamp assemblies disposed in a predetermined array with each of said assemblies including a lamp housing, an upwardly directed parabolic trough reflector mounted in said housing, an elongated iodine cycle type lamp disposed along the focal axis of said reflector, a dichroic mirror associated with each of said assemblies rigidly secured along one edge of said housing in a fixed angular position relative to the axis of a beam of light emanating therefrom so that said mirrors reflect a first portion of the optical spectrum of light in each of said beams downwardly toward said stage and transmit a second portion of the optical spectrum of light in each of said beams including the heat producing infrared portion thereof away from both said stage and said housing, duct means surrounding the tops of said mirrors, and means for exhausting the heat from said duct means.

2. For use in illuminating theatrical stagesor the like the combination comprising, a plurality of flood lamp assemblies disposed in a predetermined array with each of said assemblies including a lamp housing, an upwardly directed parabolic trough reflector mounted in said housing, an elongated iodine cycle type lamp disposed along the focal axis of said reflector, a dichroic mirror associated with each of said assemblies rigidly secured 9 along one edge of said housing in a fixed angular position relative to the axis of a beam of light emanating therefrom, said dichroic mirrors adapted to reflect av portion of the visible spectrum of light in each of said beams downwardly toward said stage and transmit the remainder of the visible spectrum of light and the infrared spectrum of light in each of said beams away fromboth said stage and said housing, duct means surrounding the tops of said mirrors, and means for exhausting the heat from said duct'means.

References Cited in the file of this patent UNITED STAIES PATENTS Edwards Sept. 15,

Paradis Sept. 15, Osterberg et a1. Feb. 26, Koch--- May 8, Beese et a1. Oct. 2, Prideaux July 9, Starwick July 30, 

1. FOR USE IN ILLUMINATING THEATRICAL STAGES OR THE LIKE THE COMBINATION COMPRISING, A PLURALITY OF FLOOD LAMP ASSEMBLIES DISPOSED IN A PREDETERMINED ARRAY WITH EACH OF SAID ASSEMBLIES INCLUDING A LAMP HOUSING, AN UPWARDLY DIRECTED PARABOLIC TROUGH REFLECTOR MOUNTED IN SAID HOUSING, AN ELONGATED IODINE CYCLE TYPE LAMP DISPOSED ALONG THE FOCAL AXIS OF SAID REFLECTOR, A DICHROIC MIRROR ASSOCIATED WITH EACH OF SAID ASSEMBLIES RIGIDLY SECURED ALONG ONE EDGE OF SAID HOUSING IN A FIXED ANGULAR POSITION RELATIVE TO THE AXIS OF A BEAM OF LIGHT EMANATING THEREFROM SO THAT SAID MIRRORS REFLECT A FIRST PORTION OF THE OPTICAL SPECTRUM OF LIGHT IN EACH OF SAID BEAMS DOWNWARDLY TOWARD SAID STAGE AND TRANSMIT A SECOND PORTION OF THE OPTICAL SPECTRUM OF LIGHT IN EACH OF SAID BEAMS INCLUDING THE HEAT PRODUCING INFRARED PORTION THEREOF AWAY FROM BOTH SAID STAGE AND SAID HOUSING, DUCT MEANS SURROUNDING THE TOPS OF SAID MIRRORS, AND MEANS FOR EXHAUSTING THE HEAT FROM SAID DUCT MEANS. 